1. Technical Field
Various embodiments relate to semiconductor memory apparatuses. In particular, certain embodiments relate to a semiconductor memory apparatus that controls an internal clock signal in a write operation to reduce current consumption.
2. Related Art
Operations that are performed within a semiconductor memory apparatus may be classified into read operations for reading and outputting data stored in cells and write operations for storing data in cells.
A semiconductor memory apparatus typically is equipped with a command decoder that receives external commands and decodes them into appropriate internal commands. In a read operation, the command decoder receives and activates a read command, and receives an external address from an address buffer to enable a word line of a cell through a decoder. Then, a sense amplifier receives a pre-decoded address to generate a sense amplifier signal to activate a bit line sense amplifier.
While the word line is enabled, a predetermined voltage is applied to a bit line, and then amplified by the bit line sense amplifier. The amplified voltage is then transferred to an input/output line through a column gate which is controlled by a column cell selection signal, and then outputted outside the chip through a series of data output paths such as a data bus sense amplifier, a latch, and an output buffer.
In a write operation, data inputted through a series of data input paths, such as an input buffer and a write driver, is loaded on an input/output line, transferred to the bit line through a column select transistor which is controlled by the column cell selection signal, and stored.
The above is a generalized description of read and write operations of a DRAM, and it should be noted that a corresponding bank is first activated to perform a write operation.
According to the semiconductor memory apparatus as described above, a write signal may be inputted only when the corresponding bank is activated. However, since it is not possible to predict when the write signal will be activated after an active command is inputted, all circuits for the write operation need to be in operation in order to handle the write operation after the active command is inputted. Therefore, an unnecessary operation is performed before the write operation is performed, resulting in an increase in the current consumption of the semiconductor memory apparatus.